Adaptive Radiotherapy Using Helical Tomotherapy for Head and Neck Cancer in Definitive and Postoperative Settings: Initial Results

Co-registration of cone beam CT and planning CT in head and neck IMRT dose estimation: a feasible adaptive radiotherapy strategy

“…9,10,12 The mean weekly cumulative CTV/PTV dosimetric differences were small, with an average difference ranging from 23.0% to 2.2%. Similarly, the average difference in delivered doses to the target volumes were within 65% for most patients and not clinically significant.…”

“…However, not all patients derive a clinically significant benefit from ART. 9,10 In addition, this strategy is labour and resource intensive, which could affect its widespread clinical implementation. As such, attempts should be made to identify the subset of patients who will benefit from ART as this could potentially improve disease control and reduce toxicities, without imposing a great stress on current radiotherapy resources.…”

Replanning Criteria and Timing Definition for Parotid Protection-Based Adaptive Radiation Therapy in Nasopharyngeal Carcinoma

“…The timing of replanning is a controversial topic in parotid protection-based ART in head and neck cancer. Someone recommended replanning when it became obvious that a tumor had shrunk, weight loss had occurred, or skin separation had reduced [7,11,12,[21][22][23], while others believe that replanning should be performed when a specific fraction has been reached [26][27][28]. Our precious study found that parotid volume variation presented a linear pattern throughout IMRT of NPC realized by HT technique, and the rate of volume variation reached its peak at the 16th fraction and then decreased gradually, suggesting that replanning is appropriate in the fourth week [14].…”

“…Patients with head and neck cancer may be subjected to significant anatomical changes during radiation therapy, changes which can cause volume shrinkage near the facial surface [6][7][8]. And parotid gland variations may result in an unanticipated overdose [9,10].…”

Three-Phase Adaptive Radiation Therapy for Patients with Nasopharyngeal Carcinoma Undergoing Intensity-Modulated Radiation Therapy: Dosimetric Analysis

“…In a study aiming to evaluate the benefits of routine midtreatment replanning to the targets or normal tissue dosimetry in patients with head and neck cancer, it was shown that patients with NPC received greatest benefits with treatment adaptation with reduction in spinal cord maximum 1.2 Gy, mean parotid dose 1.2 Gy, and parotid V26 6.3%. 16 Castadot et al 6 reimaged 10 patients during concomitant chemoradiotherapy using CT and [18F] fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) acquisition after a mean dose of 14.2, 24.5, 35.0, and 44.9 Gy. Adaptive replanning based on the updated images resulted in 10% smaller mean dose to oral cavity and 7.2% smaller dose to 2% of the spinal cord, as compared with the original plan.…”